Steam-trap



N. CURTIS.

STEAM TRAP.

(No Model.)

Patented Feb. 23, 1886.

, Incl/autor:

UNITED STATES PATENT OFFICE.

NELSON'CURTIS, OF BOSTON, MASSACHUSETTS.

STEAM-TRAP.

SPECIFICATION forming part of Letters Patent No. 336,628, dated February 23, 1886.

Application filed November Q7, i883. Serial No.112,929. (No model.)

To @ZZ whom, it may concern,.-

Be it known that I, NELsoN CURTIS, of Boston, Massachusetts, have invented a new and .useful Improvementin Steam-Traps, of which Aembodying my invention, and Fig, 2 is a partial sectional View of a modication thereof.

The invention relates to a class of steamtraps in which the opening and closing of a valve in the outlet of the steam system to which the trap belongs is controlled by the movement or position of the ieXible side of a hermeticallysealed metallic Vessel containing alcohol or other readily volatizing fluid. In the art such vessels are called4 expansionvessels.7 The flexible side bulges outward or inward, or lies in a plane, according to the temperature of the inclosed fluid, which temperature is in turn determined by the temperature, for the time being, of whatever surrounds the vessel, be the same water, or air, or steam, or combinations thereof.

The object of steam -traps of this description is to discharge the water of condensation within the general steam system at any desired temperature. In many cases it is desir* able that this water be discharged as soon as the steam takes the form of water. In other cases it is desirable to retain the water of condensation wit-hin the general system so long as such water shall have a requisite temperature for heating purposes.

Heretoi'ore the outletvalve through which the water of condensation escapes has been placed between the general steam system and the expansion-vessel; but there are several disadvantages resulting from this arrangement or location of the outlet-valve, perhaps the most important being that the apparatus cannot be used for the discharge of water of condensation at a temperature above 212, that temperature being the highest attainable by steam or water in an open vessel. Another disadvantage of the old arrangement or location of the outlet-valve consists in the liability of the expansion-vessel to become heated from extraneous sources--as, for instance, when several traps discharge into a common receptacle it not unfrequently happens that steam blowing oft' from one trap will set back into another and heat the expansion-vessel of the latter. By my invention these disadvantages are overcome. The eXpansion-vessel is placed directly within the steam system, and is controlled by the temperature of such system, irrespective of external sources of heat. It is im material whether the water of condensation is at a temperature higher or lower than 212, and it is equally immaterial whether the water of condensation is discharged into a vessel having a temperature higher or lower than itself.

.A part of my invention consists in placing the outlet-valve upon the other side of the expansion-vessel, thus bringing the expaxr sion vessel, as it were, within the general steam system-tliat is, in my apparatus` the expansionyessel, instead of being located in a vessel open to the atmosphere, and indirectly, or at times only directly, affected by the temperature of the contents of the general steam system only within limits that may exist in the atmosphere', is located within a steam-tight vessel or chamber which is Within, and thus made a part of the general steam system, and immediately affected by the temperature of the surrounding contents of the steam system, whether that temperature be high or low.

It is obvious that the variations of temperature in the contents of the general steam system may be confined to a much narrower range for operating the outlet-valve when the eXpansion-vessel is located upon the inner side of the outlet-valve and surrounded by the water or steam of the general system than when the expansion-vessel is upon the farther side of the outlet-valve in a chamber or vessel normally open to the atmosphere. A very little heat applied to the whole surface of the expansion-vessel will be sufficient to heat the contents thereof to a certain temperature in comparison with the amount of heat required to heat the same contents to the same temperature when the hea-t is applied to a small fractional part of the superficial area of that vessel. Moreover, another advantage may be obtained by locating the expansion-vessel within a chamber forming a part of a general steam IOO system. In the old form of apparatus,in which the valve or its stem is rigidly secured to the exible side of the expansion-vessel, when the elasticity of such iiexible side is lost through use, or otherwise, the valve will be opened, and the apparatus discharge cold water only under the pressure existing in the general steam system, and it is obvious that if the valve be upon the farther side of the expansion-vessel only a trifling pressure is required, since to moveY a valve of a small area the pressure is exerted upon substantially the whole arc of the flexible side of the expansionvessel, while in the old arrangement a great pressure is required, since it is exerted only upon the valve itself, and thus upon a small area. So, too, it is obvious that when the expansion-vessel is placed within the steam system the Water of condensation, or even steam, may be readily discharged into a vessel or pipe already containing steam under pressure.

Another part of my invention, however, 'consists in the employment, in a steam-tight chamber directly connected with or Vadapted to be directly connected with a steam system so as to form a part thereof, and provided with an expansion-vessel and a valved outlet for said system, as above set forth, of a spring arranged to co-operate with the expansion-vessel in controlling the valve oi said inlet.

Vhen aspring is used in the mannerherein set forth, at no time is the existence of a steampressure within the general system required, and it is preferable that the flexible side of the expansion-vessel shall be merely iiexible, and not elastic.

In the drawings, A represents the general steam system, being in fact a pipe at the end of such system.

B is a cast-ing having an inlet-arm, a, by which it is or may be attached to the steam system A. The casting -proper has open ends; butthese are closed by threaded caps or plugs b and c, the latter being adapted to receive a discharge-pipe, as shown. rlhe plug c has through it a hole, d, normally closed by a valve, C, for which the plug has a projecting support or guide, e, as shown.

D is the expansion-vessel, containing a volatile fluid, and having a flexible side, f, as before described. It is supported, as shown,

upon an arm, g, which is screwed into plug b,

as shown, and has a slot in theend for the purpose of adjustment. rIhe arm g ends in a recess in the plug b, which is closed bya cap, l1, as shown.

E is a strong spring located, as shown, between the projection e ot' the plug c and a shoulder upon the end of the stem of the valve C. This spring tends to lift the valve from its seat and open the outlet. It also keeps the valve, or, more properly, the valve-stem, in constant Contact with the iiexible side fof the expansion-vessel. Thespringisstrongenough to open the valve, except when the vo1atiliz ing-fluid within the expansion-vessel is sufficiently volatilized to overcome its force and close the valve. With this construction, therefore, no steam-pressure is required to open the valve; but in the form of apparatus shown at Fig. 2 the spring is omitted, and the valvestenl is riveted to the iiexible side of the expansion-Vessel, as shown, which form of construction will answer with steam systems of light pressure. The chamber or casting B is provided with a blow-off cock, G, as shown.

The mode of operation of the above-described apparatus embodying my improvements is obvious.

The form in which the spring is employed is particularly desirable in low-pressure heating apparatus.

I claim--- l. The combination, with a steam system, of a steam-trapv consisting of a steam -tight chamber provided with an open or free inletpassage communicating with said steam system, a valved outlet-passage, and an interior expansion-vessel, the said expansion-vessel controlling the valve of the said valved outlet-passage, substantially as described.

2. A hollow casting or chamber provided with a free inlet-passage and a valved outlet-passage, and containing an expansion-vessel and a spring, the said spring and said expansion-vessel being arranged to work in opposition to each other and govern the valve in said valved outlet-passage, substantially as described.

NELSON CURTIS.

YVitnesses:

WM. S. ROGERS, W. W. SWAN. 

